Posted
by
Unknown Lamer
on Wednesday July 11, 2012 @11:37AM
from the romney-declares-drill-baby-drill dept.

New submitter sosume writes "An article in Nature shows that temperatures in Roman times were actually higher than current temperatures. A team lead by Dr. Esper of the University of Mainz has researched tree rings and concluded that over the past 2,000 years, the forcing is up to four times as large as the 1.6W/m^2 net anthropogenic forcing since 1750 using evidence based on maximum latewood density data from northern Scandinavia, indicating that this cooling trend was stronger (0.31C per 1,000 years, ±0.03C) than previously reported, and demonstrated that this signature is missing in published tree-ring proxy records."

For 2,000 years the world was cooling, probably heading to a new Glacial Period, but now the temperatures are spiking dramatically in the other direction. Read the abstract carefully and look at the diagram. It is interesting but we'll have to see if it holds up. The current interglacial is a bit odd, we should be heading well and truly into a new glacial period, the temperature has seemed unusually stable; this paper would imply that it has not been stable at all.

it is interesting to see the tonal change of the comments over the years regarding AGW and friends.

not too long ago, just a few years or more, most comments here were vehemently lampooning skeptics of any kind whatsoever, even lumping skeptics and deniers together. skeptics were literally laughed at all over the place.

it was all large talk of IPCC glory, consensus, yellings that contradictory findings were *all* bought with dirty money, how our limited records are good enough, that how dare this one NASA guy question our belief in the contemporary climate as the golden standard, etc etc etc

I've noticed the same thing.Attacks on skeptics were personal and vindictive, not only here on Slashdot, but on every blog, mailing list, or news feed where the issue came up. The term Settled Science was thrown around like a bitchslap.

Perhaps people have learned that Argument vicieux don't help, or perhaps people have opened their eyes to more data.For what ever reason, the politically correct line hasn't wavered much (other than changing the terminology from Global Warming to Climate Change), but at least articles like the cited one get a) published and b) covered, where as they were often frozen out of publications or discussion [huffingtonpost.co.uk] in the past.

The discussion is changing, but the the politics are still in attack mode.

The paper cited is in no way denialist and only a part of the normal scientific process regarding climate science that has been going on for decades. No well researched article has been shut out. The change from Global Warming to Climate Change was driven by a conservative denialist US thinktank. The facts are not changing. They only get refined. As it is happening with evolution science. Both denialist camps use the same rhetoric, though. One has to wonder why....

The biggest problem with ALL of that line of reasoning you just espoused is that to call it being driven by a "conservative denialist thinktank" is that you're not talking science at all with that remark- IT'S RELIGION WRAPPING ITSELF IN THE TRAPPINGS OF SCIENCE.

Quite simply calling someone that doesn't agree with the posited theory (because the data is UTTERLY insufficient or the model really and honestly doesn't match the actual data without dinking with it- which is what is going on) a "denialist" means you're not practicing science AT ALL.

Whatever you choose to call them, it is clear that there are a group of people who like to style themselves "skeptics" who reject the overwhelming consensus of climate scientists--a consensus that has been reviewed and endorsed by the National Academy of Sciences (along with nearly every elite professional scientific society in the world). It is also clear that this "skeptic" point of view has been supported by an extremely well-funded public relations campaign backed by individuals and organizations who have a financial interest in sales of fossil fuels.

A distinguishing feature of this kind of "skeptic" is that their "skepticism" is notably one-sided.

For example, a genuine scientific skeptic will read the scientific literature on historical climate reconstruction and will reach the following conclusions: Reconstructing global temperatures prior to actual temperature recording is difficult, and relies on the use of "proxies," which are indirect methods of estimating temperature. These are subject to a variety of errors and artifacts, and global coverage is spotty. In addition, there is limited information regarding factors driving temperature, such as atmospheric CO2 and energy output of the sun. This is an active area of research and quite interesting, but does not really shed a great deal of light on modern global warming, which has unambiguously been demonstrated to be the result of increased atmospheric CO2.

On the other hand, the "skeptic" will reject the great mass of climate reconstructions (generally with ad hominem remarks about climate scientists or scientists in general), but will accept as gospel truth a just-published article that yields divergent results suggesting that temperatures in the past might have been higher than previous estimates. Similarly, the "skeptic" will enthusiastically embrace the "evidence" of third-hand accounts of medieval agricultural practices in northern europe as indicating that there was a warm period during medieval times--and conclude (in a bizarre jump of logic) that if medieval times were warm for some reason that (with our very limited information about climate drivers of the time) we don't understand, that we don't have to worry about the fact that we are currently seeing exactly the type of temperature increases that are predicted as a consequence of the CO2 that we are adding to the atmosphere.

Of course, a real scientist will have a very different reaction: We don't know if there was some unexplained process that warmed things up during medieval times--there isn't enough information to figure out for sure that that really happened, or if it did, what the cause was. But what if it did? That's even more disturbing. We know what the modern warming is due to--it's due to increased CO2. What if there is some other process that could produce a comparable warming in the absence of increased energy from the sun (because we've measured that, and we know it's not increasing)? Wow, that's really scary! What if that unknown process were to suddenly kick in on top of CO2? The projected warming from CO2 is bad enough, but add in some warming from some other unknown mechanism on top of that, and we could have a real catastrophe! This makes controlling CO2 even more important than I thought!

Whatever you choose to call them, it is clear that there are a group of people who like to style themselves "anti-skeptics". These people have very little understanding of Earth Sciences and believe that other people's beliefs should be determined solely by National Science Association press releases.

"National Science Association"? I'm a scientist and I've never heard of them. But it is no single science association that has reviewed the evidence and concluded that concerns about CO2 are well-founded--it is pretty much every elite scientific society in the world. Here is a partial list [wikipedia.org]

They hold dodgie polls where they claim 70% of scientists say there is some degree AGW since 1950 and the problem is serious.

There are people who are skeptical of the computer modelling predictions, people who are skeptical of whether you can model such a complex system accurately at all, people who are skeptical about the forcing values, people who are skeptical about the amount natural variation, people who are skeptical about the weightings given to solar fluctuation all the way through to people who are skeptical that the Earth hasn't warmed and believe it is actually cooling.

Yes, there are people who are "skeptical" about anything that challenges their fixed beliefs, yet remarkably credulous about such things as the ability to deduce medieval global climate from third hand accounts of agricultural practices in northern Europe.

As far funding and conspiracies go the fossil fuel industry is fairly trivial. Heartland spent $18,000 fund air fares and accommodation for one skeptic's lecture tour and this apparently is a scandal.

Just to pick a couple of examples, Koch Industries has spent over $30 million [polluterwatch.com] on lobbying efforts to create public doubt of the reality of global warming. Exxon has spent over $10M. It is worth noting that a million dollars can fund a pretty robust research project. Imagine all of the science that could have been done if these companies had spent the money funding real scientists. But clearly, they knew that funding genuine science would not help their case. So they spent it on public relations instead.

It was Jones at the CRU who did block the publication and work of other scientists trying to publish temperature records that showed the cooling since Roman times and the Medieval Warm Period and the Little Ice Age actually existed.

Yet somehow, nobody has managed to produce the unpublished work that (according to climate science "skeptic" myth) they supposedly prevented from being published. A genuine skeptic would find that odd, don't you think?

nd they managed to get them dismissed as inconsequential local variations in the IPCC report. It was the IPCC that purported to rely on peer reviewed data when over a third of its references weren't including the Himalaya glacier melting figures quoted from a mates article in WCF propaganda and put it in the report and executive summary as scientific fact.

Yet nobody has managed to find any important conclusions or recommendations of the IPCC report that are not solidly based in peer-reviewed science (and by the way, it is a climate science "skeptic" myth that the IPCC is only allowed to cite peer-reviewed studies). So the "skeptics" are reduced to picking on inconsequential, and long-corrected, errors like the one on the Himalayas. But oddly, these "skeptics" be

As you can see in the graph of TFA, it has been colder and warmer than the mean line (hint: its the red dots)As you can see in the graph of TFA, it has been colder and warmer than the mean line without us doing a lot (hint: its the red dots)

The problem is that you WANT a warmer climate and when you are proven wrong then the "cautionary principle" is called in to underline your presumptions. Data, or it wont happen.

TFA --> (hint: its the red dots)No 2000 years is nothing, let alone 50 years of industry by men. Yes, it has been slightly longer, but it was only until the postwar economic boom since we really cranked up the CO2 and other natural gases.

An article in Scientific American back around 2003-2004 (I forget when exactly) covered work that seemed to show that indeed, we were not only overdue for another ice age, but we had begun going in back a few thousand years ago. But the advent and epansion of farming (which has a tendency to warm things, for several reasons discussed in the paper/article) increasingly mitigated the cooling trend. The variance between actual temperatures and predicted temperatures for entering into an ice age was linear with the expanding acreage of farmland. So the author argued that we have been staving off the next ice age for some 4000 years. He had citations, sorry I'm too lazy to go back and find the article.

I encourage every slashdotter interested in the global warming debate to take a hard look at the Vostok Ice Core Data [wikipedia.org]. This is the most solid (ahem) evidence of global temperature change over any sort of significant time scale. It's hard data, not "interpreted" or "adjusted" measurements. Longer term data is here [wikipedia.org].

Obviously, we're currenty in an Ice Age [wikipedia.org] - when the Earth is in a warm period there is no year-round ice anywhere, not even the poles. The Earth gets much warmer during the warm periods, though mostly it warms at the poles and becomes a more even tropical temperature, IIRC.

It's possible that we're actually exiting the long term ice age, but that's a heck of a claim to make (since it's ~50 million years old, the odds would be very low), and would require a heck of a lot of evidence.

The planet has been cooling for the last 55 millions years and we are in an ice age that is getting colder in the long term. In the medium term we are in a warm interglacial and the temperature is cooling towards the next Milankovitch minimum in about 23,000 years. That is the trend you are seeing since Roman times. Without humans the planet would be cooling not warming.

Over the last century and half the climate has warmed as the the planet comes out of the Little Ice Age.Over the last half a century you have AGW on top of the natural variations due to forcing by C02, Methane, Soot, reduction in SO4 and feedback from changes in water vapour in the atmosphere.Over the last decade and a half the planet hasn't warmed because due to low solar radiation and less El Nino events.

No Nature doesn't care about us and will most likely freeze us to death. In the short term we may cook ourselves first though.

Here's one of my favorite sources [wikipedia.org]. Examine the graphs, and you'll find that few inter-glacial periods lasted over 20 thousand years, and we've been in ours for... 20 thousand years. Add to that the trend over the last 10 million years, and it seems that these ice ages are getting colder and colder. Straight line projection for another 10 million years puts us in snow-ball Earth territory. It's entirely possible that higher life on land was (and still may be) nearly at an end.

However, if you just want to be anal, like most Fox News fans when it comes to the topic of global warming, we can just take NASA's satellite measurements of surface temperatures since 1972. The Earth is warming. There's no way an intelligent person can look at that graph and not draw the obvious best line fit conclusion. Actually, that's not quite right, because there are plenty of intelligent people who are simply incapable of seeing what they don't want to see.

All the article says is that forcings related to orbital mechanics may have been larger on a millenium time scale than estimated before. Even that is speculation - the core of the paper is presenting a improved method for evaluating tree ring proxies. The paper, however, does not call into doubt that the industrial age has added a significant greenhouse gas forcing, which gets bigger as we continue to add CO2 and methane.

All the article says is that forcings related to orbital mechanics may have been larger on a millenium time scale than estimated before. Even that is speculation - the core of the paper is presenting a improved method for evaluating tree ring proxies. The paper, however, does not call into doubt that the industrial age has added a significant greenhouse gas forcing, which gets bigger as we continue to add CO2 and methane.

It calls into doubt the idea that global warming itself is a catastrophe. It suggests that humanity thrived on a significantly hotter world than any living person has known.

It shows that humanity thrived in a world that was about as warm as now. A world which had no additional greenhouse gas forcing like the one added by the industrial age. That's the data presented. The rest is made up conjecture by you.

Well said, both posts. As I re-read the register article after reading the Nature article, I'm surprised by the quotes from Professor-Doktor Jan Esper. It appears the only thing the study proved was previous N-Scale readings disagree with current TRW readings, and that TRW readings are suspected to be more accurate than N-Scale or Lake/River readings.

As far as the current temperatures go, we're dealing with the same heat the Romans did. All *that* proves is it was fuck-off hot then, and it's fuck-off hot now. As for the trend, if you plot the data all the way out, we're still in a cooling trend, and the "hockey stick" is there, but a graph with this many historical deviations from the mean is utterly worthless for predicting the future, at least by itself. A hockey stick can turn into a plateau and come down, or just keep going up and up, but there's no way to know from that graph alone.

I wish people could understand that and look at the studies that actually investigate AGW instead of the ones that just measure past trends.

2000 years ago the planet wasn't supporting as large of a population. The problem with global warming isn't the temperature increase--it's the rise in sea level, which will place a great many cities (and countries) underwater.

I don't think anyone has seriously suggested that global warming will bring on an extinction-level event. But I would say that a few million drowned Bangladeshi counts as a "catastrophe."

Interesting - several major city ports from Roman times, referenced in the New Testament (I think Ephesus is one of them), are now miles from the Mediterranean. If sea level rises, then maybe those cities might become ports again.

Are you implying that the Bangladeshi aren't smart enough to get out of the way of a 0.4mm annual rise in ocean levels? Or is it that they are so short they will drown in 18-59cm of water that will rise in the next 90 years? Your post does not make that clear.

I think you need to re-evaluate your understanding of sea level rise and any "catastrophes" it may cause. There are loads of antropocentric problems that will arise in the next 100 years as a result of the rise, but people drowning is most decidedly NOT one of them.

Exactly. We're already seeing this problem with Mexico and the USA. A lot of the illegal immigrants from Mexico are coming up to the US because there's not enough water going south in the Colorado river (LA is using it all up), making much of northern Mexico unusable for farming as arid areas like that depend on irrigation. So, with no economic opportunities, they're moving to the nearest place where opportunities exist, which is the USA immediately to their north. Problem is, many Americans (except for business owners looking to take advantage of dirt-cheap labor) don't want them here for various reasons.

When large groups of people want to migrate elsewhere, this is an inevitable problem in modern times where there's zero unclaimed livable land left. The people who already live on that land usually don't want a lot of newcomers, and if they do, they have very strict conditions and rules, such as Canada where you either need to deposit $300K into a Canadian bank account or you need to have some skill they want; dirt-poor, uneducated, unskilled people aren't welcome there.

There is a very recent exciting discovery with nano materials to both demineralize sea water AND mine the minerals from the sea water.

This allows water with the perfect salt level for irrigation- which opens up a lot of arable land. It's really exciting stuff. Common materials, under 1% of the current energy requirements, and the minerals extracted could well cover the cost of water purification.

It calls into doubt the idea that global warming itself is a catastrophe. It suggests that humanity thrived on a significantly hotter world than any living person has known.

Possibly. The actual paper is far less glib in its conclusions than the article linked in The Register. It suggests that data from Scandinavia might require climate researches to recalibrate their tree ring models -- which if true makes the scenario you describe *a possibility*, but that is far from proof. That possibility is interesting, but obviously it'll take more than tree ring data from one small corner of Europe to overturn the scientific consensus.

It's silly to jump up and say "aha!" when something like this comes up, because things like this have come up in the past and will continue to do so in the future. Every theory has contradictory data; in fact 5% of papers can be expected to report spuriously significant results. That's why individual papers can't overturn the scientific consensus, because that asks: where does the current preponderance of evidence lead? There's always been some evidence that weighs against AGW. For example I remember a similar back in the 80s (before AGW was a political football) about t unhe accuracy of Royal Navy sea temperatures recorded in the 1700's and 1800's. They collected the water to be measured in canvas bags, which would have cooled their contents by evaporation. When something like this comes up you've got to ask (1) is it real? (2) how practically significant is it?

This paper may or may not prove to be scientifically important. But what is unquestionably important is that this paper shows it *is* possible to publish papers which weigh against the scientific consensus in climate research, and to do so in a prestigious peer reviewed journal. Researchers will pig pile on this researcher's claims, because that's the way the process works. If the paper stands up to that, then it *might* be the start of a shift in consensus. But I wouldn't hold my breath if I were you. Papers that *might* be the start of a shift are far, far more common than lines of inquiry which successfully lead to such a shift.

There is no such thing as a "negative" impact on the biosphere. There are only changes, and these changes are neither positive nor negative, except from a distinctly human perspective. The biosphere doesn't give a rat's ass what happens to it. Life will adapt and evolve under any conditions, just as it did for 4+ billion years before us, and will long after we're gone.

It is likely that the paper is not trying to either 'prove' or 'disprove' AGW.

Most likely, the scientists who wrote it noticed a problem with the way tree rings are measured, and thought, "Wow! With this we could get an article published in Nature!" They may have even had old dreams of nobel prizes flash before their eyes (though no doubt replaced by more 'proper' thoughts). Scientists are not always motivated by the same things other people are.

The authors are not set out to "prove" global warming, because there is not much left to prove. They acknowledge the consensus amount of CO2 forcing in the paper. All they do is recalibrate other parameters that frankly change nothing substantial. In particular not, as this paper only deals with one proxy data set among many and gives highly localized data for northern Scandinavia.

You are aware that the original hockeystick has been shown again and again in different, completely independent proxies? I guess you are, but you choose to ignore it. It is not about todays temperatures being unprecedented - that they are clearly not. But then again, you know that this is a strawman. It is the current increase of greenhouse gas forcing that is unprecedented. If you would actually read the paper in question, you'd realize that they at no point question this forcing. Denialist cherrypicking again.

The problem is that this isn't relevant to the social issue of global warming, and many "skeptics" will claim that it is relevant. Even if the change in temperature ends up being a blip on the radar in geological time, it only takes a few years of drought to decimate food stores and cause a world-wide pandemic. THIS is the issue that should be relevant to us these days, and I'm afraid that all these newly minted arm-chair scientists (more accurately described as big business apologists) are going to ensure that we delay action until it is too late.

Another thing I should say is that we have a very reliable model for showing that increased CO2 can cause warming on a small scale. "skeptics" claim that the burden of proof is on those who say it will happen on a large scale, despite evidence that it IS happening on a large scale. This has never been the way science works. The burden of proof is on "skeptics" to explain why a reproducible, verifiable model on a small scale won't work on a large scale. They have no evidence, and are quite dishonestly trying to shift the burden of proof back on the scientists, knowing full well that on a large scale it will take a much longer time to acquire the kind of evidence they are seeking.

An analogy would be if we said that since Pluto's orbit is 248 years, then we've probably only recorded it orbiting the sun a few times (arguably less than that if we only count modern record-keeping), and so therefore we haven't collected enough data to determine that orbital mechanics apply to Pluto. After all, maybe the 7th observed cycle around the sun it will veer off into space, violating all of our current models. This type of reasoning is nonsense. Science always seeks to apply the simplest, most general theory to all systems. Science only creates a new theory if it absolutely has to. The burden of proof would be on the orbital mechanics "skeptics" to show why it would behave differently on a large scale, not on those who can show without a doubt that it happens on a small scale, and have shown that all measurable results indicate it is happening on a large scale. The idea that we should start with two separate models, one for large scale and another for the small scale, is precisely the opposite of what science seeks to do, and is a severe mis-representation of science.

No, the burden of proof is always on the person making the affirmative statement. It's usually very difficult to prove a negative. However, in many cases we're willing to accept a theory that makes sense and fits all the observed data.

It's difficult to make generalized, unqualified statements, and that is the property that makes something difficult to prove, not the fact that it's negative or positive. Whether or not it's negative or positive doesn't matter, it's the fact that something is a sweeping statement that makes it hard to prove. Proving that something always happens is just as hard to prove as proving that something never happens.

Next, if you'll reread my post, you'll notice that what I was saying was qualified with the condition that we have a small scale example that is reproducible with a high degree of confidence. You then mis-represented what I was saying, by arguing against the idea that "the burden of proof is always on the skeptic". I didn't say that. I said, specifically, "The burden of proof is on "skeptics" to explain why a reproducible, verifiable model on a small scale won't work on a large scale. " That's VERY different than saying, "The burden of proof is ALWAYS on the skeptics." Your tactic is what is know as a straw-man fallacy, as you are making an argument against something that I did not say.

Look, one of the big differences between religion and science is that religion and mythology will often create new theories for everything. You have a god for lightning, thunder, volcanoes, etc. Or you have a single god who is doing a bunch of different things. The goal of science is to get to the essence of what is going on, and wherever possible, unify our understanding into as simple of a model as possible. We only create separate models when we absolutely have to, and any reasonable hypothesis for weather should start with the models that we already know and understand (such as the greenhouse effect on a small scale), not a blank slate. Then, when we see evidence that the small scale model does apply to larger systems, we should apply this model to both small and large systems (with less confidence for the large system) until we see evidence that says otherwise. We don't simply say, "Gee, we've only collected a few decades of official evidence, let's hold off for a few millenia."

Looking at the graph you can see at least 6 instances of abrupt temperature increases that are identical to the last one and at least 5 times temps exceeded the trend.

In that context, our recent increases are not unique. If you want to pin the recent increases on Man and CO2, then you need to explain how the past increases came to be and why the current increases are not driven by the same forces.

This is true if you are talking about Europe, but IMO the AMOC (Atlantic Meridional Overturning Current) makes all European climate analysis too chaotic to be of any real use, globally. Look up the Elder and Younger Dryas, when France was reduced to arctic tundra (twice) while the rest of the world was largely unaffected. Whoever is claiming that their warming trend was global (based on one data point) is claiming victory without even playing the game Europe's climate may be the most chaotic in the world, and its temperature changes have always been decoupled from (and occasionally opposed to) the rest of the planet. There is already too much evidence that the medieval warming period was isolated for this to be overturned so easily.

WRONG the sceptics demand a continued rise in CO2 in the air. The scientists demand no further increases in CO2 concetrations.

Close, but no cigar. The skeptics don't demand a continued rise in CO2, and you would likely be hard-pressed to find an AGW skeptic who believed that we should stop R&D toward the goal of reducing CO2 emissions. What the skeptics are saying is that the "OMG! OMG! CATASTROPHE! Divert all money into halting CO2 emissions NOW! (and keep giving us grants so we can continue to produce doomsday predictions) or we're all DOOMED!" attitude of the AGW proponents would have us all throwing money down a rathole, diverting huge amounts of funds from actually doing something useful in our depressed economies and using it for programs that won't have the benefits the warmists are claiming.

No, actually that's a farcical parody invented to let you blow off the people you disagree with. It has no connection to what they actually say.

Even the way you refer to them - "AGW proponents" - shows just how misleading your thought processes are. They are not "proponents" of global warming. In fact, they are not as group in favor of anything at all. The only thing they have in common is that they accept the overwhelming body of evidence really does show what it shows. That is their defining quality, just as the defining quality of "AGW skeptics" is that they deny the evidence shows what it really does show. You're trying to conflate two completely different issues: what are the facts, and what is a sensible response to them? Accepting the reality of global warming does not imply any particular policy, but you can't intelligently choose a policy until you accept the facts. You don't like particular policies that have been proposed, and you are using that as an excuse to ignore the facts.

And contrary to what you say, lots of global warming skeptics believe we should stop all R&D toward reducing CO2 emissions. After all, they don't believe there's anything wrong with CO2, so why should we waste money trying to reduce it?

The burden of proof is on "skeptics" to explain why a reproducible, verifiable model on a small scale won't work on a large scale.

Yet, we're supposed to take the claim that it will on faith...

This has never been the way science works.

Right in one...

An analogy would be if we said that since Pluto's orbit is 248 years, then we've probably only recorded it orbiting the sun a few times (arguably less than that if we only count modern record-keeping), and so therefore we haven't collected enough data to determine that orbital mechanics apply to Pluto.

Not even close, in fact your analogy is so far off that 'hyperbole' is a distant fading memory in the search for superlatives to describe it. Why? Because we have accurate long term models of orbital mechanics - and we do not have them for climate science.

The idea that we should start with two separate models, one for large scale and another for the small scale, is precisely the opposite of what science seeks to do, and is a severe mis-representation of science.

True, but your emotionally charged rhetoric and numerous logical errors and appeals to faith aren't science either. Science is demonstrating a connection between the various scales, and backing up that connection with data - not saying "it's not our responsibility to finish up the job".

Note, I'm not a skeptic, but you need to learn a thing or three about science before even attempting to defend it. Confused smokescreens like yours do no one any favors.

Since the CO2 content of the atmosphere has measurably increased from 280 to 400 ppm within the last 150 years, it is pretty clear that the "easier plant growth" does in fact not neutralize much? most? all? of the CO2. So, your "fact" is clearly in contradiction to observed reality. Start at the point and think...

The problem is that this isn't relevant to the social issue of global warming, and many "skeptics" will claim that it is relevant. Even if the change in temperature ends up being a blip on the radar in geological time, it only takes a few years of drought to decimate food stores and cause a world-wide pandemic. THIS is the issue that should be relevant to us these days, and I'm afraid that all these newly minted arm-chair scientists (more accurately described as big business apologists) are going to ensure that we delay action until it is too late.

Another thing I should say is that we have a very reliable model for showing that increased CO2 can cause warming on a small scale.

First off, your scare-mongering helps no one and nothing. The work presented in this paper includes the claim that past climate forcings have been up to four times as large as the current 1.6 W/m**2 that is due to antropogentic CO2 since 1760.

Let me repeat that for everyone who missed it: there have been extended periods--centuries--in the past that have experienced orbital climate forcings that are up to 6.4 W/m**2 as opposed to our current 1.6 W/m**2. The proxy temperature also shows sharp upward jumps of the kind that appear in the 20th century.

If you deny this, you are denying scientific evidence. Feel free to do so if that's what your politics dictate, but don't pretend you're defending science in the process.

It follows from this that the Earth's ecosystem, the polar bears, and so on, are capable of weathering the kind of thing we are doing to the world. This is what the science is telling us. Human economies may be more fragile. Or not.

Secondly, your claim that we have "a very reliable model" of the complex non-linear system that is the Earth's atmosphere and oceans is simply false. We have a set of more-or-less unphysical models that contain all the science we can find, but are still parameterized and approximated in ways that make computational physicists shudder. These models have not been developed by computational physicists but by climatologists, and that's a problem.

None of this is to say that we should go on dumping gigatonnes of garbage--including CO2--into the atmosphere. But this cherry-picking of the scientific results is about 10% as bad on the pro-AGW side as the anti-AGW side, and that's pretty damned bad. No matter who wins, science loses.

The idea that we should start with two separate models, one for large scale and another for the small scale, is precisely the opposite of what science seeks to do, and is a severe mis-representation of science.

So much wrong with this it deserves two replies.

When modeling non-linear systems like the Earth's climate, multi-scale models are exactly what we do. Your analogy to a quasi-linear system like orbital mechanics is so completely wrong-headed as to be funny.

Furtheremore, there was actually a deeply serious debate in the orbital mechanics community in the late '80's as to whether the solar system was even stable. Due to extremely subtle defects in our models it appeared that our long-term integrations of orbits exhibited chaotic behaviour in the relevant mathematical sense... orbits were still "fairly" stable but acquired random phases and whatnot over time, and tiny changes in starting conditions in the early solar system resulted in substantially different orbital phases today.

This all turned out to be false, but it took a decade and some extremely careful mathematical and computational work to prove it.

Yet compared to modeling the climate the solar system is child's play.

So why do people like you believe climate models the way a fundamentalist believes the Bible? It can't be because of the quality of the science, nor your understanding of it, because while the science is good it is no-where near good enough to bear the weight of the conclusions you jump to.

Either it is the long-term climatic change that the IPCC and others have been warning about, or it isn't. You say "a few years of drought" - that isn't long-term climate at all, but short-term weather patterns. Anyway, the US east of the Rockies (which I'll bet is where you are) is yammering about hot temperatures and drought being signs of global warming. Meanwhile, lots of the rest of the planet is having a cool, rainy summer. Your local weather is exactly that: local, and short term.

I am definitely a skeptic. There is no question that CO2 contributes to a greenhouse effect, however, there is no evidence (and never has been) that this triggers large positive feedback cycles. It has all been based on computer models, and most of the predictions of those models have been wrong.

The headline is rather misleading, it's as the author of the article is trying to debunk global warming. Which isn't the case; he is merely talking about possible errors in a common way to estimate temperatures. From the article:

These findings, together with the missing orbital signature in published dendrochronological records, suggest that large-scale near-surface air-temperature reconstructions9, 10, 11, 12, 13 relying on tree-ring data may underestimate pre-instrumental temperatures including warmth during Medieval and Roman times.

In other words: estimates of temperature in medieval/Roman times based on tree ring data may well be too low.

In other words: estimates of temperature in medieval/Roman times based on tree ring data may well be too low.

Global Warming Alarmists will point to this and say we have reversed a cooling trend that has lasted at least 2000 years.

Global Warming Denialists will use this to show that it's been warming in the past and previous data that shows global warming is now suspect.

I think this new data shows that we don't have a clue what we are talking about when it comes to the climate. I believe the best we can do is take measurements and say what it's like RIGHT NOW. Judging the past is inaccurate. In the future, we'll look back on today and say, "those guys didn't know what they were talking about!" I agree with our future selves.

But there were much less of us and the available food to human ratio was at least POTENTIALLY better for humans during the Roman period... Not much we can do for 2 or 3 billion people of crops burn or flood.

They also kick up in roman times... a lot higher... and in the middle ages...

You know what? This might be hard to believe... but I don't think we're very good at predicting the weather...

All that aside... pollution is bad for many other reasons that don't involve global warming. So maybe you need to stop beating a dead horse and focus on something a little more tangible like "we're going to run out of oil rather soon" or "That shit causes cancer"

Good. AGW is a definite problem, and people like you don't really help the situation. By playing the old "weather isn't climate, you retards!" card you're overlooking the fact we have long been applying small scale models to predict large scale changes. This is why Charlie's joke about predicting the weather was pretty damn good.

The point you seem to miss, all high and mighty up there, is that claiming we can predict long term climate change based on historical weather patterns and/or small scale and short term models hurts the position of changing how we consume energy. It's just as silly as those who say "well it isn't hotter HERE, so there's no warming going on at all, liar!"

There are so very, very, very many reasons to effect energy changes that focusing entirely on something that is inherently unreliable, and being snarky about it, is worse than a waste of time. Yes, it's getting warmer. Yes, it's likely our consumption has a quantifiable but unmeasurable effect on it. It's also true that we are gonna run out of oil, it's expensive, and we need to be self-sustaining.

By the way, he knows the difference between weather and climate, as do I. Your'e the one who assumed we didn't. So, the joke becomes about using weather (a small and short term historical model, with high precision and increasingly low accuracy as we move back in time) to predict climate (a large and long term model, with less precision and low accuracy). What other large-scale predictions have we made using small-scale models?

Uh, I don't see a "sharp kick up" when we get to the industrial age in those graphs. When are you considering the start of the industrial age? Traditionally, it's the 1750-1800 range that is considered the start of the industrial age. I see a step up when we hit the 1930's, then a bowl like curve for the rest of the 20th century.

Indeed, RealClimate notes [realclimate.org] that if you remove dendrochronology records from Mann et al (2008), you actually get a lesser pre-industrial cooling trend [realclimate.org]. Of the dozens of independent lines of evidence, tree rings have long been one of the *least* suggestive of disproportionately high GHG forcing versus other forcings, so it's always funny to see them called out as though the case for global warming rests on them.;) (The reason that they're often called out is because they're *really tricky* to use well; so many things affect tree growth that have to be accounted for, and the factors vary greatly from location to location)

The "hockey stick" graphs were never proven in the first place. Taking a dimensionless tree ring history and scaling and gluing it to a thermometer record based on a brief period of co-movement, and then ignoring a subsequent period of strong deviation by handwavingly saying that "something must have caused" tree rings to stop being affected by temperature, was always terrible and rotten science.

To provide specific details, this refers to the famous "Hockey Stick" chart. The statement from the Climategate emails about "hiding the decline", as referenced here: http://climateaudit.org/2009/11/26/the-deleted-portion-of-the-briffa-reconstruction/... refers specifically to ignoring the subsequent period of deviation between tree ring records and thermometer records, after just in the years prior taking that relationship as extremely strong and using it to give scale and units to the tree ring records.

To illustrate the problem:

- Let's say you want to assess how much food people ate during the medieval times.- The only long term record you have is an overview of how many apples were harvested from a sample of orchards for 1000 years.- And your short term record going back 100 years is however much more detailed, and shows how much food people have eaten recently- It turns out that for a period of 50 years it looks like there was a strong degree of co-movement between these measures.- So you basically overlay these and scale the orchard record until it co-moves with the food record, letting you estimate food consumption 1000 years ago.- Oh wait, for the subsequent period of 50 years, it turns out that measured food consumption has actually wildly diverged from orchard records and there is no relationship detectable.- This should indicate that the previous 50 year period you have used to scale orchard records was simply a statistical fluke.- But you ignore this and conspire with your friends to "hide" these later 50 years, pretending that the relationship between food data and orchard output is actually very strong.

I'm pretty sure more CO2 in the atmosphere is very beneficial to plant life and will help it flourish in forests and agriculture, not sure about in the ocean(i.e. plankton) since disolved CO2 in water leads to acidity issues. It is possible mother nature could counterbalance increasing CO2 levels by putting CO2 consuming organisms in to overdrive.

Ocean physics, chemistry and biology is so complex I seriously doubt there is any one who can claim they have a accurate holistic understanding, could model changes in it with any accuracy or make any reliable predictions about what it will do.

The one issue I have with the global warming chicken littles is that there is no inherent reason that recent CO2 levels or temperatures are some kind gold standard that must be maintained at all costs. Our planet has been all over the map on both temperatures and atmospheric chemistry, whose to say that some of those other levels weren't actually better overall.

On the other hand the rate at which are changing the atmosphere's composition thanks to industrail scales, and the rate at which we could change global temperatures and sea levels may prove to be very problematic to a lot of species including our own, especially since, as a species we are very fond of building large amounts of infrastructure on the coasts.

We could have a runaway climatic catastrophe, we could muddle along, or mother nature could eventually counterbalance our mistakes. Absolutely no one knows, anyone who claims to know with certainty is not being particularly truthful, anyone who claims to have an accurate computer model of our climate is really being untruthful.

It is safe to say burning fossil fuels at our current rate probably isn't a particularly great idea. It obviously does pose a greenhouse gas risk, no one knows how much, and equally important we are going to eventually run out of them so we really should be working hard to find alternatives. Pretty much the last thing the U.S. government should be doing is subsidizing fossil fuels with things like huge tax breaks for oil companies but good luck getting rid of those.

On the other hand taxing fossil fuels in to the ground to force the switch to alternatives isn't exactly a great idea either. It hammers your economy and it really hammers lower income people who spend a lot of their income on energy.

I'm pretty sure more CO2 in the atmosphere is very beneficial to plant life and will help it flourish in forests and agriculture

Only if CO2 is the limiting factor. If e.g. water or nitrogen are the limiting factor in plant growth, excess CO2 will lead to extremely minor benefits, if any.

The one issue I have with the global warming chicken littles is that there is no inherent reason that recent CO2 levels or temperatures are some kind gold standard that must be maintained at all costs.

What the "chicken littles" are saying is that our life and society has already adapted to existing CO2 levels. Anything much higher or much lower than existing levels will probably require further adaptations. For instance, the location of high-yield arable land can change.

Yeah, you can ask anybody who studied antique history. We all know that the romans grew wine in England. How do people think they managed to do that? Of course it was warmer back then than nowadays.
And then in the 1750's we had a very cold period where we can deduce from paintings that the East Sea was often frozen shut in the winter.

Temperatures were lower than in Roman and medieval times, and falling... until the recent warming kicked in.This is yet another hockey stick. I can't see how the Register is turning it into anti-AGW propaganda. Read the Nature article, not the Register.

Looking at the graph you can see at least 6 instances of abrupt temperature increases and at least 5 times temps exceeded the trend.

In that context, our recent increases are not unique. If you want to pin the recent increases on Man, then you need to explain how the past increases came to be and why the current increases are not driven by the same forces.

I don't have evidence at hand, but purely anecdotally, every climate related article I have seen on ElReg was solidly rooted in the denialsphere. Their journalistic reputation stems from good tech reporting - when they stray out of their competence, they clearly show a lot of bias.

Grats, slashdot for the misleading title. It is not like it was unknown that there has been a cooling trend on a 1000-year timescale. It may have been stronger than previously thought. This paper estimates it at -0.32 K/ka - Mann 2008 had it at -2.something K/ka. It was to be expected that the denialist would latch onto some cherry picked sentences - business as usual.

A team lead by dr Esper of the University of Mainz has researched tree rings and concluded that over the past 2,000 years

That's odd, according to the image from the paper [nature.com] the trend in question is from 138 BC–AD 1900. Of course, after reading the Guardian article, it's clear that the only papers in Nature worth this "reporter's" time are those that confirm his professional opinion on the state of global temperatures. Tell me, why exactly didn't they construct a trend from 138 BC–AD 2012? Was that 1900-2012 range more difficult to acquire for some hilarious reason? I mean, the data is in the graph right there.

You can select special time ranges, you can select windows and you can look at millions of years of data and say that temperatures right now are no big deal. But when you start to look at the rate of change (even in the paper's graph linked above) and you notice recently we're starting to approach rates that are increasingly less frequent in the historical record, I think it's okay to start to talk about what could be causing it. I mean now we're talking about the last two thousand years and yeah, that's an acceptable window but if we never swing back down below to average it out, at what point are you going to admit that the theory of C02 affecting global average temperatures has some weight to it? Trust me, if we increase by 2 degrees Celsius, you can increase this window back five millennium and say "Hey, they used to have temperatures warmer than we do now." It's entirely possible to endlessly play this game by moving the goal posts. But I don't think the Earth is going to be able to adapt as well as humans do to rapid change. I guess the only thing that can convince people is time and repercussions that actually inconvenience humans.

Maybe this paper has nothing to do with AGW? Or are you saying AGW is nothing but goalseeking, and any data point that lessons the potential impact, or lessens the fear of a global apocalypse is thus unwelcome?

The forcing is substantial over the past 2,000 years, up to four times as large as the 1.6Wm2 net anthropogenic forcing since 1750 (ref. 4), but the trend varies considerably over time, space and with season5. Using numerous high-latitude proxy records, slow orbital changes have recently been shown6 to gradually force boreal summer temperature cooling over the common era.

That's the second sentence of the summary. How can it not be about AGW when it talks about this having an effect opposite of "net anthropogenic forcing since 1750"? Did you even read the paper?

Or are you saying AGW is nothing but goalseeking, and any data point that lessons the potential impact, or lessens the fear of a global apocalypse is thus unwelcome?

No, I did not say that. This paper looks legitimate and should be published and was published. It is interesting. My problem was that they seemed to have cherry picked a date range and then The Guardian took that and ran with it. In my opinion they flat out misi

"if you were standing in the forest, you could be hit by a falling tree. therefore, because we cut down this tree and killed that guy standing over there, we're not responsible, because getting killed by falling trees happens naturally"

Finding the weak points in various temperature proxies and using that knowledge to improve the overall accuracy of the temperature record is a good thing, and a normal part of the scientific process. Sensationalist reporting of the type The Register engages in just serves to inflame the debate without adding anything useful to the discussion.

Yes global warming is real, but most of the nimrods are running around claiming that the Heat wave was proof of it. I got so sick of trying to explain it that I started saying, "yes, and it's going to go up another 4 degrees every month, you had better start selling your Florida property before others find out! Minnesota is the new florida buy land near fargo!

This retarded press release was written by someone that can't even GRASP the science, or purpose, of the published paper. Please, for the love of god, stop posting science topics on/. based on what some ingrate with a word processor posts up to some off-beat web periodical with a political agenda. The "graph" given by the press release article doesn't even appear in the paper and is missing a lot of annotations and descriptions necessary to properly evaluate the data. Important things. Like a Y-axis. And the method used to develop the data- surprise, most of it's modeled/reconstructed. Which is FINE if you grasp what they were trying to do with this publication.

And before I jump into the paper can we clearly define what journal an article is published in? Saying "Nature" is misleading. It's "Nature: Climate Change". Not similar, at all.

The paper is a methods paper. It's outlining a very interesting way to get at fine-resolution temperature fluctuations on a not-so-far-back time scale. Additionally, the moving average rise in temperature isn't suggesting it was HOTTER back then than now (as this submission and the press release indicate) but that instead our ESTIMATES of how hot it was are off.. SLIGHTLY. How far off? Here, let me copy primary literature for you. I hear that's good journalistic practice.

"...These findings together with the trends revealed in long-term CGCM runs suggest that large-scale summer temperatures were some tenths of a degree Celsius warmer during Roman times than previously thought.
It has been demonstrated4 that prominent, but shorter term climatic episodes, including the Medieval Warm Period and subsequent Little Ice Age, were influenced by solar output and (grouped) volcanic activity changes, and that the extent of warmth during medieval times varies considerably in space. Regression-based calculations over only the past millennium (including the twentieth century) are thus problematic as they effectively provide estimates of these forcings that typically act on shorter timescales. Accurate estimation of orbitally forced temperature signals in high-resolution proxy records therefore requires time series that extend beyond the Medieval Warm Period and preferably reach the past 2,000 years or longer6.
Further uncertainty on estimating the effect of missing orbital signatures on hemispheric reconstructions is related to the spatial patterns of JJA orbital forcing and associated CGCM temperature trends. First, the simulated temperature trends, indicating substantial weakening of insolation signals towards the tropics, can at present be assessed in only two CGCMs (refs 7, 8). More long-term runs with GCMs to validate these hemispheric patterns are required. Whereas the large-scale patterns of temperature trends seem rather similar among the CGCMs, the magnitude of orbitally forced trends varies considerably among the simulations. Additional uncertainty stems from the weight of tree-ring data and varying seasonality of reconstructed temperatures in the large-scale compilations. Although some of the reconstructions are solely composed of tree-ring data, others include a multitude of proxies (including precipitation-sensitive time series) and may even include non-summer temperature signals. Some of these issues are difficult to tackle, as the weighting of individual proxies in several large-scale reconstructions is poorly quantified. The results presented here, however, indicate that a thorough assessment of the impact of potentially omitted orbital signatures is required as most large-scale temperature reconstructions include long-term tree-ring data from high-latitude environments. Further well-replicated MXD-based reconstructions are needed to better constrain the orbital forcing of millennial scale temperature trends and estimate the consequences to the ongoing evaluation of recent warming in a long-term context."

I wish I could just copy past the whole article into peoples brains and make them understand the difference between science and sensationalism.

The fact that climate change took place centuries or even millennia ago doesn't prove that it was not caused by people. Humans have been doing things to affect the climate for a long time.

Charles C. Mann, in his excellent book 1493, discusses a theory that the "Little Ice Age" (a period of cooler than usual temperatures from roughly 1550-1800) was the result of the Columbian Exchange. Basically, the Native Americans had populated large portions of the New World, and in so doing had cleared most of the forest lands. After Columbus and his successors arrived, the Native Americans died at an insane rate from European diseases, and new forests grew across vast swathes of the Americas. This in turn resulted in far lower CO2 levels and consequently lower temperatures.

A few seconds of searching brings up this article [upi.com] saying "prehistoric small-scale agricultural societies had already caused widespread ecological change" and "Prehistoric people practiced deforestation to reorient their settlements and intensify corn production". The theory of it causing the little ice age is probably wrong, but Native American impact on the environment was significant and shouldn't be dismissed out of hand. Remember the arrival of Native Americans was a major extinction event as well.

When Al Gore and other politicians start saying 'the time for discussion is over' on such a complex subject, technically-trained people know that the time for discussion and study is just starting. This article summarizes an interesting study that points to warmer temperatures in roman times. Archaeological studies also support this. For example, many of the seaports that those Romans used are now far inland thanks to a lower sea level due to cooling temperatures. AGW believers minds are firmly closed to any idea that does not include imminent peril from 'hockey-stick' warming. The reality is that the support for AGW caused by atmospheric carbon dioxide concentrations rests on very crude computer models of the global climate that will probably be the subject of horse laughs 50 years into the future.

Thanks to the link below I got to read the actual paper - the standard of reporting on this issue is atrocious. The paper looked at tree data from a small area of Scandinavia. Also pointing out that they have experienced a lot less warming in recent years than other northern areas.... Hmm do you think that may be true 1000's of years ago - it could have been warmer or cooler than the global average we don't know. So for CLIMATE in Lewis's article read WEATHER, i.e. Local effects for which it is extremely inaccurate to extrapolate to the world. Glad my knee jerk feeling that this was a daft extrapolation has been verified by the paper."

There is a difference, in that they are different, but the article doesn't say anything about this study disproving AGW, only that it disproves the assertion that it is now hotter than it has ever been in the last X,000+ years.

My kingdom for a modpoint today. The AGW issue is so emotional that discussion of data becomes impossible. No, it's worse: even the fact that there IS data to discuss is an implied attack on one position or the other.

My take on the entire thing is it's good for us to work on being more responsible, environmentally. We can and should find ways to be more efficient, cleaner, and self-sustaining, and make an aggregate profit while doing so. Sometimes it's the right thing to make a change to the way we d

The paper does not dispute that the climate is changing as a result of human pollution.

The paper calls into question previous methods of evaluating historical data, and asserts that orbital changes have had a greater effect on the Earth's climate over the past 2000 years than CO2 emissions have had over the past 200 years (note that the timescales different by a factor of ten).

There is still a nice big spike coinciding with the industrial era.

Do not pick and choose words or results from scientific papers. The scientists who published this paper are part of the X who agree that CO2 emissions are warming the planet.

The Micheal Mann hockeystick used in An Inconvenient Truth is substatntially located aroudn th e same lattitide, using European and Russian trees. So if you are going to call this into question, you have to also call Mann's hockey stick into question. Ironically, they will both live or die together. What this paper does is correct for orbital mechanics, so in a way, it is a refinement that tilts the hockey stick a bit.

The current hockeysticks, which completely validate the original Mann paper, are based on multiproxy reconstructions that range from polar ice cores to tropical lake sediments to coral reef proxies etc. etc. But yes, as you said, if the orbital forcing is indeed as strong as they speculate from one highly regional source, the hockey stick gets perhaps a bit tilted. It's fundamental message stays the same, though.